Basic question about creating watermarks for video.

Hey, I'm new here, from Toronto. I've had gimp for a while but never got the motivation to learn to use it til now. Anyways, I've been trying to create text logos to be used as water marks for videos. Making the the text images is quite easy and the options under "create logo" are great. The problem is I don't know how to isolate just the text. Is there an easy way to do this? I was told to save files as "GIFS" to place on videos. Apologize if this is an overwhelmingly newb question, any help is much appreciated.